Combination agitation and transfer unit for suspended cells



Sept. 23, 1969 w, J, DURYEA ETAL 3,468,520

COMBINATION AGITATION AND TRANSFER UNIT FOR SUSPENDED CELLS Filed May 12, 1967 RUBBER amp/mu 3 q -u/v/r/mr PLUG /9 --8T/RRER SLEEVE 6 H sPm/va CLAMP 4 :3 1 PADDLE' a 5 TRANSFER was i y 6' 2 INVENTORS W/LL/AM JAMES DURYEA GEORGE SPENCER B077 ATTORNEY United States Patent US. Cl. 259-39 3 Claims ABSTRACT OF THE DISCLOSURE A combined transfer tube and reciprocating paddle stirrer is mounted as a unit in a stopper which can be introduced into a bottle or other container. A vent is provided through the same stopper. The transfer tube and paddle are both bent so that when moved closely together the whole assembly can be inserted into a bottle without disassembly. After insertion, the paddle shaft is connected through a rubber sealing diaphragm to an eccentric drive from a suitable power source, such as a motor. The motor turns the shaft and eccentric connections cause the paddle stirrer to reciprocate slowly through an are slightly less than 180.

The transfer tube is bent so that it extends substantially to the bottom of the container, which permits transferring substantially all of its contents. The slow reciprocation of the stirrer produces a uniform suspension without cell lysis, a suspension of which is to be transferred. At the same time, the stirrer and unitary transfer tube assembly can be easily removed from the container and conveniently sterilized.

Background of the invention It is necessary to disperse sterile suspensions of whole, intact cells, and this requires both stirring and suitable transfer so that the cells do not settle out and a uniform concentration of suspension can be transferred. In the past stirring has utilized a magnetic stirrer having a stationary shaft and a rotating magnetic bar suspended from the end of the shaft through an interlocking swivel chain. The bar is rotated in a magnetic field and the length of the bar and chain are maintained so that they clear the transfer tube.

Serious problems in practical use have arisen. First of all, extreme care must be taken to ensure that the rotating magnetic bar does not hit the transfer tube, which would result in slowing it down or even completely stopping it. When a heavy cell suspension is being dispersed and transferred, the vision of the bar stirrer is obstructed and improper operation cannot readily be detected. With the stirring devices described above, uniform operation often does not result and there is inadequate agitation. When this occurs, a considerable batch of material may be lost due to the uneven distribution of cells, particularly when the cell suspension is a heavy suspension, because it cannot be seen in time that the stirring is not operating properly. Nevertheless, this was the best that could be obtained in the past and occasional malfunction was tolerated.

Summary of the invention The present invention utilizes a bent transfer tube with a reciprocating shaft and paddle stirrer which is also bent, the whole being in a unitary plug which is passed through a stopper. When the stirrer paddle is turned to a point adjacent to the bent end of the transfer tube, the whole can be introduced into a large bottle, for example a 9- liter bottle, and the stirrer shaft is then connected through a rubber diaphragm for sterile sealing purposes to a motion transfer unit, which is driven from a motor with an eccentric drive that causes the shaft to reciprocate slowly through an are slightly less than The whole assembly is readily sterilized and remains sterile because the rubber diaphragm prevents contamination from the atmosphere during operation. At the same time, the slow reciprocating paddle does not rupture walls of cells and the bent transfer tube permits transferring material down to the last contents of the large bottle which serves as a reservoir.

No problem is presented with unreliable stirring, as is the case with a magnetic stirrer, and the agitation remains constantly properly proportioned to maintain the cell suspension uniformly dispersed but without resulting in rupture of cell walls. The whole system is air tight and sterile, and the delivery tube and stirrer sleeve can be easily sterilized as a unit between uses. It is preferred to make the transfer tube and stirrer assembly of material such as stainless steel, but other materials which have adequate resistance to sterilizing conditions may be used, such as glass. The stopper can be of any suitable material, such as rubber or other elastomer, and the choice depends only on the conditions of prospective operation. This flexibility of material choice is a practical advantage.

Brief description of the drawings FIG. 1 is a section through a container with transfer tube and stirrer inserted, and

FIG. 2 is a horizontal section along the line 22 of FIG. 1.

Description of the preferred embodiments A framework 1 carries a platform 2 on which a reservoir 11, in the form of a 9-liter glass bottle, rests. The bottle is held against curved projections 3 of the framework by means of a spring clamp 4. A bent transfer tube 5 and stirrer sleeve 6 are formed into a unitary plug 19, which extends through a stopper 9. The stirrer shaft 7 is bent at its bottom end and carries a paddle 8, which can be slightly inclined so that when it is reciprocated as will be described below, the contents of the bottle 11, a suspension of intact cells, is maintained sufiiciently agitated so that a uniform dispersion is produced and is maintained. The stopper 9 also carries a vent tube 10, which may be of stainless steel if desired.

The shaft 7 connects into a motion transfer unit 12, passing through a rubber diaphragm 13 which seals the stirrer sleeve and prevents atmospheric contamination from entering between the sleeve and the shaft.

The motion transfer unit 12 is driven by a motor 14 through gearing 15 and an eccentric drive 16 which causes the unit 12, and with it the stirrer shaft, to reciprocate slowly through an arc of about 180. The rate is important and a suitable stirring rate is represented by 14 or 15 rpm. in order to prevent foaming of high pro tein suspensions. The position of the paddle 8 in the other extreme of its reciprocation is shown in dashed lines in the drawing.

When it is desired to transfer suspension from the reservoir 11, the vent tube 10 can be connected to a source of sterile air and the bent upper portion of the transfer tube also connected by flexible tubing to containers into which suspension is to be transferred. This type of connection is well known and is not changed by the present invention and, therefore, is not shown in order to avoid confusing the drawings. Control is effected by suitable valves in the sterile air supply and in the flexible tube extending to the container to which material is to be transferred. This is also conventional and is not changed by the present invention. Since flexible tubing is used, it is possible to use simple flow controls, such as pinch cocks, but as this is also conventional it is not shown.

After the transfer of as many portions of suspension as is desired and the bottle 11 is emptied, the drive mechanism is removed from the framework 1, as is shown diagrammatically by the mounting 17, which is maintained tight by a screw 18. The stirring and transfer tube assembly can be disconnected from the motion transfer unit 12 and the paddle removed from the stirrer sleeve by sliding the paddle stem through the rubber diaphragm and the assembly can then be washed and sterilized, if desired, before being used on the next batch.

What is claimed is:

1. A combined agitation and transfer assembly for sterile transfer of suspensions of intact cells in a container comprising,

(a) an assembly of a bent transfer tube, a bent stirrer shaft and a stirrer sleeve mounted in a stopper suitable for insertion into the container,

(b) the transfer tube and stirrer being dimensioned so that they extend substantially to the bottom of the container, the stirrer being provided with a paddle surface at its extremity,

(c) the transfer tube and stirrer both having their bent portions at the ends substantially at the bottom of the container after insertion and the bends being sufliciently parallel in one position of the stirrer so that when the stirrer is turned to the position where the bent portion is substantially parallel to that of the transfer tube the assembly can be inserted into the container,

(d) means for supplying gaseous medium under sterile conditions through the stopper,

(e) means for oscillating the stirrer shaft in an are up to approximately and (f) flexible means for sealing the opening between the stirrer shaft and stirrer sleeve.

2. A device according to claim 1 in which the paddle is inclined to cause agitation throughout the whole of the contents of the container.

3. A device according to claim 2 in which the sealing means between stirrer shaft and sleeve is a rubber diaphragm.

References Cited UNITED STATES PATENTS 780,621 1/ 1905 Ripley 259-122 2,084,651 6/ 1937 Mecklenburg et a1. 2,660,518 11/1953 White. 2,829,931 4/1958 De Pree et al. 2,859,020 11/ 1958 Eddy et al. 23292 XR 2,958,517 11/1960 Harker et a1. 259108 XR 3,182,970 5/1965 Ivanoff 259128 XR 3,368,723 2/ 1968 Hardeman 25939 XR WALTER A. SCHEEL Primary Examiner JOHN M. BELL, Assistant Examiner US. Cl. X.R. 

